Alternative Message Custom CSS

Hi,
Everything is working great with the modal box pop-up and alternative message. However I can’t get the custom CSS to work for the alternative message via the plugin settings. I read the older forum Q&A about Responsive Text Box where you said to use the following CSS example:

.an-alternative {
    background-color: #fff;
    border: 2px solid #AD3428;
    padding: 10px;
}

I enabled “Clone Ad Container: Custom Mode” and pasted the individual style elements in the “Custom Mode CSS properties ( Comma separated )” field, e.g. “background-color: #fff, border: 2px solid #AD3428” etc, saved, flushed, regenerated random files, cleared the browser cache, closed & reopened the browser but it had no effect.

Next I cleared the Custom Mode CSS Properties field and pasted the above CSS code “.an-alternative { … }” into the “Custom CSS ( Advance users )” editor. It looked great with syntax highlighting – nice touch! Saved, flushed and regenerated but still no effect after clearing the browser cache, closing and opening the browser.

I didn’t find the .an-alternative style in Firebug or the Chrome Inspector when examining the alternative messages.

What did work was appending the above CSS to the CSS/an-style.min.css with the line breaks and white spaces removed for minification. The alternative message container is responsive, too!

I checked the documentation on b-website.com but the screens don’t show a Custom CSS example.

What am I doing wrong?

Thanks

https://wordpress.org/plugins/adblock-notify-by-bweb/